Patent GB-1035055-A (GB)
Title: Woven wire memory matrix
IPC: G11C11/04
Filed: 1963-09-20
Abstract: 1,035,055. Magnetic storage apparatus. KOKUSAI DENSHIN DENWA KABUSHIKI KAISHA. Sept. 20, 1963 [Oct. 15, 1962; Jan. 28, 1963; May 6, 1963; May 13, 1963; June 22, 1963; Aug. 22, 1963 (3); Sept. 4, 1963], No. 37155/63. Heading H3B. Various magnetic matrix stores are described in which the row and column conductors are linked together by a woven construction or by the column conductors having one or more turns around each row conductor, and in which the row conductors are coated with ferromagnetic material having an easy direction of magnetization, independent storage elements being formed by those parts of the ferromagnetic material at the row and column crossing points. The row conductors may be formed of copper; phosphor bronze, beryllium copper or aluminium wire which is coated with a thin layer of permalloy either directly or on to an insulating covering, Figs. 1(A), 1(B) (not shown). In each case the magnetic material has an easy direction of magnetization which may be either parallel to or circumferentially of the axis of the wire, Figs. 2(A), 2(B) (not shown). Information is stored in the usual manner by applying a pulse Id, Fig. 3, to a selected matrix conductor to rotate the magnetization axis to the hard direction, and subsequently terminating the pulse while an information pulse Ii + or Ii - is applied to an orthogonal conductor. Consequently, the magnetic state reverts along the easy axis in a direction determined by the information pulse polarity. Read out is effected by the leading part of the Id pulse which induces an output Ip + or Ip - in the orthogonal conductor of polarity determined by the direction of magnetization along the easy axis. Alternating pulses may also be used. In Fig. 5, information write-in and non-destructive readout is effected by alternating Id pulses and unidirectional information pulses I 1  +, I 1 -, the induced alternating output I p  + (o) or Ip - (#) being of twice the frequency and having a phase o or # determined by the data stored. Similar outputs are obtained in Fig. 6 in which the pulses Id and Ii are both alternating, the identity of the data to be stored being determined by the phase o or # of the higher frequency Ii. Fig. 7(A) illustrates a woven construction in which the magnetic row conductors X1-X5 are each associated with the equivalent of 1 turn of each column conductor Y1-Y5. In Fig. 8(A) the spacing of the column conductors is maintained by the use of a rectangular insulating coating, Fig. 8(B) (not shown). Fig. 9 is a modification of Fig. 7(A) in which substantially straight column conductors are used without a return portion. In Fig. 10(C), each column conductor 6 has one or more turns around each row conductor 3; Fig. 10(D) is a modification using similarly arranged return portions of conductors 6. Figs. 11(A) and 11(B) show winding arrangements intended to minimize noise due to unwanted inductive couplings. Fig. 12(C) (not shown) is a modification of Fig. 9 in which each column conductor comprises several filaments connected in parallel, one method of parallel connection being shown in Fig. 12(D). Each column conductor may be passed around each row conductor several times by connecting filaments in series as shown in Fig. 12(E). Magnetic coupling between adjacent storage elements may be reduced by the use of discrete magnetic coatings spaced along each conductive row wire. The coatings may be formed by providing an insulating layer 10, Fig. 14(C) on spaced portions of each conductive row wire 1, followed by controlled deposition of magnetic material on to the insulated parts of the wire. The insulating layer may initially be deposited over the whole length of the wire 1, in the form of light-sensitive material, unwanting portions being removed by a photoetching process. An alternative process involves removing unwanted magnetic material from a uniformly coated wire by photo-etching. A further method of preventing magnetic coupling between adjacent storage elements on uniformly-coated wires is to provide non- magnetic conductive rings on the row conductors intermediate the crossing points as shown at 16 in Fig. 18. The rings may be separate integers or conductive layers, or as shown in Fig. 20(A) may be notched plates 17a, 17b engaging a plurality of row conductors X1-X3. An alternative form is shown in Figs. 21(A) and 21(B) in which the row conductors 3 are located in slots 25 of a conductive member 19. Projections on each side of the slots engage in corresponding apertures in an insulating strip 21, and are soldered at 24 to a printed circuit 22 on the rear surface of the strip. Other alternatives are single or multiple wire loops 26, 27, Figs. 22(A), 22(B), and shaped conductive strips 28a, 28b in contact, Fig. 23. The latter embodiment may be extended by forming the strips as conductive layers 29, Fig. 24(B) on insulating plates 31, two plates in face-to-face relationship as shown in Fig. 24(A) supporting the row conductors X1-X4 and column conductors Y1-Y4 in spaced relationship.